Simplify the following expression: $k = \dfrac{8t + 8}{2r - 4s} - \dfrac{4r + 2}{2r - 4s}$ You can assume $r,s,t \neq 0$.
Explanation: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{8t + 8 - (4r + 2)}{2r - 4s}$ $k = \dfrac{8t + 6 - 4r}{2r - 4s}$ The numerator and denominator have a common factor of $2$, so we can simplify $k = \dfrac{4t + 3 - 2r}{r - 2s}$